The present invention relates in general to controlling translation and more particularly concerns a rigid compact and completely mechanically operated microscope bridge that provides an operator with rapid rough positioning, fine positioning, coarse focusing and fine focusing, includes an automatic locking system that locks the microscope at the position set by the operator whether power is on or off and includes safety features that allow the drive to slip when the microscope hits the viewing platen or the microscope rhomboid is caught under a cross beam or overhanging arm on an associated light table while being raised. Other safety features include a brake that prevents the microscope from being manually pushed into the viewing platen and torque limiting clutches for preventing damage to the drive mechanisms.
A typical prior art bridge is described in U.S. Pat. No. 3,606,693 granted Sept. 21, 1971, on a FILM VIEWING MEANS of Grimes and Kasdorf. That patent describes a master overhead carriage system that includes a quick release coupling between an X travel unit and a Y travel unit, and a Z travel instrument carrying unit on the X travel unit having a rotary instrument supporting ring. The patent discloses coarse and fine focusing adjustments in the Z travel using a gravity feed for preventing feeding of the instrument into the viewing stage while permitting rapid instrument elevation with a manually operated clamp or lock for adjusting the instrument around the X axis. An electrical clutching arrangement automatically couples X and Y fine feed means and includes an electrical decoupling for permitting rapid instrument positioning along the X and Y axes.
It is an important object of this invention to provide improved apparatus and techniques for controlling translation.
It is another object of the invention to achieve the preceding object while effecting the translation rapidly, safely and precisely.
It is still another object of the invention to achieve one or more of the preceding objects while automatically locking the apparatus to maintain a selected position following actuation of the apparatus to effect translation and establish the selected position.
It is a further object of the invention to achieve one or more of the preceding objects with reliable apparatus that is relatively easy and inexpensive to fabricate taking into consideration the precision, speed and safety with which translation is controlled.
It is still a further object of the invention to achieve one or more of the preceding objects with apparatus easily operable by relatively unskilled personnel to effect controlled translation for rapidly and precisely establishing a desired position of a device, such as a microscope, carried by the apparatus.